Higher Dose Irradiation for Malignant Spinal Cord Compression: Long-Term Results of the RAMSES-01 Trial

Despite the increasing popularity of upfront decompressive surgery, there are still patients with malignant spinal cord compression (MSCC) and expected longer-term survival receiving irradiation alone. In these patients, local progression-free survival (LPFS) may be improved with doses beyond the commonly applied regimen of 10 × 3.0 Gy. A prospective phase 2 trial (RAMSES-01) investigated the benefit of two regimens, 15 × 2.633 and 18 × 2.333 Gy, compared with a 10 × 3.0 Gy (historical control). Patients in the phase 2 cohort had significantly better local progression-free survival (LPFS) after 1 year. Since recurrent MSCC-related motor weakness is a serious situation, it must be avoided as long as possible. In this respect, it is important to know whether the superiority of 15 × 2.633 and 18 × 2.333 Gy found in the RAMSES-01 trial still exists after 2 or 3 years. This led to the current study. In the phase 2 group, 2- and 3-year LPFS rates were 93.1% and 93.1%, respectively, and survival rates were 54.2% and 36.1%, respectively. According to propensity-adjusted Cox regression analyses, radiotherapy regimens in the phase 2 cohort resulted in significantly better LPFS at 2 (p = 0.017) and 3 (p = 0.013) years. In contrast, survival was not significantly different (p = 0.251 and p = 0.288, respectively). Radiation myelopathy and pathologic vertebral fractures were not observed in any group. Given the limitations of this study, irradiation 15 × 2.633 or 18 × 2.333 Gy may be an alternative option for patients with MSCC and longer expected survival treated with irradiation alone.